I just made one of these and fought with all the various curves. I believe I won the fight. I assume you're having trouble with the curved dish part, not with folded support part.
First, the reflector dish -
I shaped it against the end of a fat paintbrush, then against the handle of a small diagonal cutter. Got some wrinkles the first time and the curves were not symmetrical. Then flipped it end for end and shaped it some more. Three or four times with this process and the curves were even with no wrinkles remaining.
Next, the support behind the dish –
I used a Hold ‘n Fold tool to hold it down the long centerline, and then bent the free side by 45 degrees. You could clamp it with any straightedge along that long axis against a piece of glass, then use a straight blade to get under the part and bend it up by 45 degrees.
To get the gentle curve on the long axis I rolled a coin inside the vee shape against the soft part of my fingertip. Then needed to flatten it a bit in the center to make it conform to the back of the dish.
Good luck,
Rick